This invention relates generally to beverage filter cartridges of the type disclosed in U.S. Pat. No. 5,840,189 (Sylvan et al.), the disclosure of which is herein incorporated by reference in its entirety, and is concerned in particular with an improved method of forming and inserting the filter elements into the cup-shaped containers of such cartridges.
In beverage filter cartridges of the type under consideration, as depicted in FIGS. 1-3, a cup-shaped container xe2x80x9cCxe2x80x9d has a generally flat bottom 10, a side wall 12 which joins an enlarged diameter collar 14 at a shoulder 16, and an upper rim surrounded by an outwardly extending radial lip 18. An inverted frustroconical filter element xe2x80x9cFxe2x80x9d subdivides the interior of the container C into first and second chambers 22, 24. An extract xe2x80x9cExe2x80x9d, which may typically comprise ground coffee, is contained within the filter element F in chamber 22, and a lid xe2x80x9cLxe2x80x9d is applied to the cup lip 18 to complete the package. The lid L and container C coact to hermetically encapsulate the beverage extract E, and both are yieldably pierceable. In use during a brewing cycle, a tubular inlet probe 26 pierces the lid to admit pressurized hot water into chamber 22 where it infuses the beverage extract to produce a beverage. The beverage passes through the filter into chamber 24 from which it is removed by a tubular outlet probe 28 pierced through the cup bottom 10.
The container C and lid L may be fabricated from commercially available impermeable materials, including plastics, papers, metals such as aluminum, etc. The filter F may comprise one or more layers of permeable heat sealable materials, including for example a blend of cellulose and thermoplastic fibers, such as SUPERSEAL supplied by J R Crompton, of Atlanta, Ga.
The role of the filter element F is critical to achieving a successful brewing cycle. In addition to possessing sufficient strength to withstand rupture by the pressure of the hot water being admitted via probe 26, the bottom of the filter must be reliably centered to avoid being pierced by the outlet probe 28. Moreover, the filter must be securely attached to the cup side wall, for otherwise the extract is likely to escape into chamber 24 where it will mix with the outflowing beverage.
Generally stated, the objective of the present invention is the provision of an improved method for efficiently forming, precisely inserting and reliably securing filter elements in the cup-shaped containers of the above-described beverage filter cartridges.